Messages in this thread | | | Date | Sat, 1 Oct 2011 18:19:49 +0300 | From | "Kirill A. Shutemov" <> | Subject | Re: [PATCH 06/11] cgroups: Add res counter common ancestor searching |
| |
On Sat, Oct 01, 2011 at 05:07:03PM +0200, Frederic Weisbecker wrote: > On Sun, Sep 18, 2011 at 10:59:32PM +0300, Kirill A. Shutemov wrote: > > On Tue, Sep 13, 2011 at 01:11:26AM +0200, Frederic Weisbecker wrote: > > > Add a new API to find the common ancestor between two resource > > > counters. This includes the passed resource counter themselves. > > > > > > Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> > > > Acked-by: Paul Menage <paul@paulmenage.org> > > > Cc: Li Zefan <lizf@cn.fujitsu.com> > > > Cc: Johannes Weiner <hannes@cmpxchg.org> > > > Cc: Aditya Kali <adityakali@google.com> > > > Cc: Oleg Nesterov <oleg@redhat.com> > > > Cc: Andrew Morton <akpm@linux-foundation.org> > > > Cc: Kay Sievers <kay.sievers@vrfy.org> > > > Cc: Tim Hockin <thockin@hockin.org> > > > Cc: Tejun Heo <tj@kernel.org> > > > --- > > > include/linux/res_counter.h | 3 +++ > > > kernel/res_counter.c | 22 ++++++++++++++++++++++ > > > 2 files changed, 25 insertions(+), 0 deletions(-) > > > > > > diff --git a/include/linux/res_counter.h b/include/linux/res_counter.h > > > index de4ba29..558f39b 100644 > > > --- a/include/linux/res_counter.h > > > +++ b/include/linux/res_counter.h > > > @@ -147,6 +147,9 @@ static inline void res_counter_uncharge(struct res_counter *counter, > > > res_counter_uncharge_until(counter, NULL, val); > > > } > > > > > > +struct res_counter *res_counter_common_ancestor(struct res_counter *l, > > > + struct res_counter *r); > > > + > > > /** > > > * res_counter_margin - calculate chargeable space of a counter > > > * @cnt: the counter > > > diff --git a/kernel/res_counter.c b/kernel/res_counter.c > > > index 0cc9c7e..22f07cc 100644 > > > --- a/kernel/res_counter.c > > > +++ b/kernel/res_counter.c > > > @@ -91,6 +91,28 @@ void res_counter_uncharge_until(struct res_counter *counter, > > > local_irq_restore(flags); > > > } > > > > > > +/* > > > + * Walk through r1 and r2 parents and try to find the closest common one > > > + * between both. If none is found, it returns NULL. > > > + */ > > > +struct res_counter * > > > +res_counter_common_ancestor(struct res_counter *r1, struct res_counter *r2) > > > +{ > > > + struct res_counter *iter; > > > + > > > + while (r1) { > > > + iter = r2; > > > + while (iter) { > > > + if (iter == r1) > > > + return iter; > > > + iter = iter->parent; > > > + } > > > + > > > + r1 = r1->parent; > > > + } > > > + > > > + return NULL; > > > +} > > > > Your implementation is O(n*m). > > > > What about: > > > > struct res_counter * > > res_counter_common_ancestor(struct res_counter *r1, struct res_counter *r2) > > { > > struct res_counter *iter; > > int r1_depth = 0, r2_depth = 0; > > > > for (iter = r1; iter; iter = iter->parent) > > r1_depth++; > > for (iter = r2; iter; iter = iter->parent) > > r2_depth++; > > > > while (r1_depth > r2_depth) { > > r1 = r1->parent; > > r1_depth--; > > } > > while (r2_depth > r1_depth) { > > r2 = r2->parent; > > r2_depth--; > > } > > > > while (r1 != r2) { > > r1 = r1->parent; > > r2 = r2->parent; > > } > > > > return r1; > > } > > While applying this (works well btw) I realize you rewrote the patch. > > Can you give me your "Signed-off-by:" so that I correctly set the > authorship and the tags that come along?
Sure.
Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
-- Kirill A. Shutemov
| |